IMPROVING SCANNING TIME OF AN ANTENNA
An array antenna having radiating patches arranged in an array. Each of the radiating patches being connected to multiple variable phase shifters, wherein each phase shifter can produce a phase shift within a limited range. A switching arrangement is operable to connect different sets of variable phase shifters to the radiating patches to thereby scan the beam to desired directions.
This application claims priority from U.S. Provisional Application No. 63/399,570, filed Aug. 19, 2022, the disclosure of which is incorporated herein by reference in its entirety.
BACKGROUND 1. FieldThe subject disclosure relates to improvements in response time of scanning array antenna, especially beneficial when used in conjunction of electronic devices, such as, e.g., variable dielectric constant antenna.
2. Related ArtThe subject inventor has previously disclosed designs of array antennas which utilize variable dielectric constant (VDC) materials to enable software control of the antenna. See, e.g., U.S. Pat. Nos. 10,505,280 and 10,686,257, which are incorporated herein by reference in their entirety. As explained in these patents, when an appropriate electrical field is applied, the molecules rotate an amount that correlates with the strength of the applied field, and when the field is removed the molecules return to their relaxed state, thus changing the dielectric constant and affecting the transmission of an RF signal traveling in proximity to the molecules. However, the temporal response to application of the field, i.e., Trise or aligning the domains, is much faster than the temporal response to turning off the field, i.e., Tfall or relaxing the domains. That is, Trise and Tfall are inherently asymmetrical. Trise is controlled by the potential applied across the VDC, while Tfall is controlled by the relaxation time of the VDC when the potential is removed. Hence, Tfall is inherent property of the VDC material, which drastically slows the reaction time of the antenna. In certain applications, such as those disclosed by the subject inventor in the above cited patents and in U.S. Pat. Nos. 7,466,269, 7,884,766 and 10,199,710, which are incorporated herein by reference, it is highly desirable to have the turn off response at speeds similar to the turn on response.
SUMMARYThe following summary of the disclosure is included in order to provide a basic understanding of some aspects and features of the invention. This summary is not an extensive overview of the invention and as such it is not intended to particularly identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented below.
Disclosed embodiments overcome the inherent asymmetry in the Trise and Tfall times by changing the control of the domain, such that changes in the dielectric constant is caused mostly using application of potential, and minimizing reliance on natural relaxation. For example, when the VDC is used for phase shifting in a scanning array antenna, each phase shifter is activated as much as possible on its Trise slope, which is much faster than the Tfall slope, and hence the overall antenna response time is improved. Thus, rather than following attempts to increase the speed of Tfall, the inventors' innovations circumvent or minimizes the reliance on Tfall when scanning the beam.
In disclosed embodiments, multiple variable phase shifters are coupled to each radiating element. Each of the variable phase shifters is programmed to operate within a sub-band of the total shift band for the radiating element. The amount of required phase shift at each given instance is transmitted by the controller (e.g., a FPGA) and a switch, such as a multiplexer, determines which of the phase shifter should be activated to achieve the desired shift. By calculated selection, each instruction from the controller can be translated by the multiplexer to cause a phase shift that relies on Trise, rather than on Tfall.
Disclosed embodiments provide an antenna, comprising: a plurality of radiators arranged in an array; a plurality of transmission lines, each coupled to one of the radiators; a plurality of variable phase shifters divided into a plurality of subgroups, each of the subgroups interposed between one of the transmission lines and one of the radiators; a controller outputting a signal indicative of amount of phase shift to be activated for each of the radiators; a switch interposed between the transmission lines and the plurality of variable phase shifters, the switch receiving the signal from the controller and connecting selected variable phase shifters to selected transmission lines according to the signal.
By the embodiments disclosed herein, an array antenna is provided, comprising: a variable dielectric constant (VDC) plate; a plurality of radiating patches provided in an array over the VDC plate; a plurality of variable delay lines provided over the VDC plate and below the radiating patches; a plurality of fixed delay lines provided over the VDC plate and below the radiating patches, each fixed delay line connected to one of the variable delay lines; a corporate feed having a plurality of ports; a ground plane; and a plurality of switches configured to selectively connect each of the ports to a selected variable delay line and to selectively connect each of the radiating patches to a selected fixed delay line. The antenna may have m fixed delay line, wherein n of the fixed delay lines introduce zero delay, and wherein n<m. The antenna may have m variable delay lines and n fixed delay lines, wherein n<m. Each of the switches may have one port and at least two throws. In the antenna, the variable delay lines may be provided on one layer and the fixed delay lines may be provided on a second layer above the first layer. Alternatively, the variable delay lines and the fixed delay lines may be provided on the same layer.
Other aspects and features of the invention would be apparent from the detailed description, which is made with reference to the following drawings. It should be appreciated that the detailed description and the drawings provides various non-limiting examples of various embodiments of the invention, which is defined by the appended claims.
The accompanying drawings, which are incorporated in and constitute a part of this specification, exemplify the embodiments of the present invention and, together with the description, serve to explain and illustrate principles of the invention. The drawings are intended to illustrate major features of the exemplary embodiments in a diagrammatic manner. The drawings are not intended to depict every feature of actual embodiments nor relative dimensions of the depicted elements, and are not drawn to scale.
Embodiments of the inventive system and method for improving response time of variable dielectric constant antenna will now be described with reference to the drawings. Different embodiments or their combinations may be used for different applications or to achieve different benefits. Depending on the outcome sought to be achieved, different features disclosed herein may be utilized partially or to their fullest, alone or in combination with other features, balancing advantages with requirements and constraints. Therefore, certain benefits will be highlighted with reference to different embodiments, but are not limited to the disclosed embodiments. That is, the features disclosed herein are not limited to the embodiment within which they are described, but may be “mixed and matched” with other features and incorporated in other embodiments.
As explained above and in the above-cited patents, control of the phase of each radiator is done by changing the dielectric constant of the VDC by application of appropriate potential, generally a DC voltage. However, while a phase change that requires increased potential can be achieved relatively fast, a phase change that requires reduced potential is relatively slower, since the VDC domains must relax naturally. This problem is solved using the invention disclosed herein, which is exemplified by the following embodiment.
In conventional antenna array, the phase of each radiator is controlled by a single phase shifter. Conversely, according to disclosed embodiments, the phase of each radiator is controlled by multiple variable phase shifters, each variable phase shifter being tailored to operate within a dedicated phase shift range. In its most simplistic form, each radiator is switchably coupled to two variable phase shifters, a first phase shifter operable for phase shift in the range of 0°-80°, and a second phase shifter operable for phase shift of 180°-360°. Thus, for any phase shift between 0°-80°, e.g., 75°, the appropriate potential is applied to the first phase shifter and a switch is operated to connect the first phase shifter to the radiator. Conversely, for any phase shift between 180°-360°, e.g., 175°, the appropriate potential is applied to the second phase shifter and the switch is operated to connect the second phase shifter to the radiator. Of course, any number of phase shifters can be used, and the more phase shifters are used the faster the scanning of the beam can be achieved.
To illustrate, in the example of
In general terms, the antenna has a plurality of variable phase shifters arranged as plurality of subgroups of variable phase shifters, each subgroup including n variable phase shifters, and each variable phase shifter within the group introduces a phase shift of up to 360°/n, wherein n is a number greater than 1. However, in embodiments employing overlap, each variable phase shifter within the group introduces a phase shift of up to (360°/n)+m, wherein m<(360°/n). For example, when n=2, m is smaller than 180°, and if m=90°, as shown in
In the example of
The fixed phase shifter does not rely on the VDC layer to generate the phase shift, so that Trise and Tfall do not apply to the fixed phase shifters. The fixed phase shifters may be made by, e.g., inserting a dielectric slab or ferrite in the transmission line. The dielectric constant and signal travel length within the fixed phase shifter are selected to generate the desired fixed phase shift. Using such a structure the fixed phase shifter is a passive device and operates independently of the VDC layer. The fixed phase shifters may be any off-the-shelf devices or may be formed integrally within the layers of the array antenna.
To illustrate, to generate a 175° phase delay in the signal using the embodiment of
A partial solution to minimize the need to rely on Tfall in the embodiment of
Also, if the next desired phase is within an overlap, an algorithm can be developed to determine whether to just utilize the Tfall of the current shifter or activate the overlapping phase shifter, in order to minimize the time it takes to reach the next phase shift. For example, the change in phase may be so small that letting the domain relax may be faster than activating the overlapping shifter and utilizing Trise. For example, the decision can be made based on time comparison of Tfall of the current shifter versus Trise of the overlapping shifter:
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- If (Trise(ϕo→Ω2)>Tfall(Ω1→Ω2)), then activate overlap shifter;
- wherein Ω1 is the current phase, Ω2 is the next desired phase and ϕo is the current phase of the overlapping shifter (presumably zero, at least for the embodiment of
FIG. 3 ).
According to another example, the decision can be made based on minimizing phase distance. In this specific example, it is assumed that Trise is three time as fast as Tfall, but an accurate multiplier can be derived experimentally for different implementations. Taking the distance from the current phase to the desired phase using the current phase shifter as (Name PS, taking the and distance from the current phase to the desired phase using the overlap phase shifter as φbk_PS, the decision to revert to the overlapping (backup) phase shifter could be made by considering:
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- If Øbk_PS≤3·ØsamePS Then backup=True
As disclosed in, e.g., the above cited U.S. Pat. Nos. 10,505,280 and 10,686,257, embodiment of the array antenna can be fabricated using multiple layers, wherein each layer is dedicated to a certain function, e.g., radiating layer, phase shift layer, variable dielectric layer, ground/common layer, etc. Therefore, in various embodiments implementing the multiple phase shifters per radiating element, the required tasks can be relegated to different layers in the stack.
Referring to
Vias 860 are formed in the dielectric spacer 807 and connect to variable delay lines 820 and 822, such that each of the variable delay lines 820 and 822 is electrically connected to one of the fixed delay lines 815. The switch, in this example SPDT 852 connects one of the variable delay lines 820 or 822 to port CF. Consequently, a signal traveling through variable delay line 820 experiences the variable delay introduced by variable delay line 820 and its corresponding fixed delay line 815 (e.g., 0°), while a signal traveling in variable delay line 822 experiences the variable delay introduced by variable delay line 822 and the fixed delay introduced by the respective fixed delay line 815 (e.g., 180°).
The delay in the variable delay lines 820 and 822 may be controlled by the variable dielectric constant (VDC) plate 840 having variable dielectric constant material 844. While any manner for constructing the VDC plate 840 may be suitable for use with the embodiments of the antenna, as a shorthand in the specific embodiments the VDC plate 840 is shown consisting of upper binder 842, (e.g., glass, PET, etc.) variable dielectric constant material 844 (e.g., twisted nematic liquid crystal layer), and bottom binder 846. In other embodiments one or both of the binder layers 842 and 844 may be omitted. Alternatively, adhesive such as epoxy or glass beads may be used instead of the binder layers 842 and/or 844.
In some embodiments, e.g., when using twisted nematic liquid crystal layer, the VDC plate 840 also includes an alignment layer that may be deposited and/or glued or be formed on the upper binder 342. The alignment layer may be a thin layer of material, such as polyimide-based PVA, that is being rubbed or cured with UV in order to align the molecules of the LC at the edges of confining substrates.
The effective dielectric constant of VDC plate 840 can be controlled by applying DC potential across the VDC plate 840. For that purpose, electrodes may be formed and connected to controllable voltage potential. There are various arrangements to form the electrodes, and several examples are disclosed in the above-cited patents. In the arrangement shown in
At this point it should be clarified that in the subject description the use of the term ground refers to both the generally acceptable ground potential, i.e., earth potential, and also to a common or reference potential, which may be a set potential or a floating potential. Similarly, while in the drawings the symbol for ground is used, it is used as shorthand to signify either an earth or a common potential, interchangeably. Thus, whenever the term ground is used herein, the term common or reference potential, which may be set or floating potential, is included therein. Also, at times the subject disclosure utilizes the terms delay line or phase shifter interchangeably, as a delay line generates a phase shift in the signal traveling thereon.
As with all RF antennas, reception and transmission are symmetrical, such that a description of one equally applies to the other. In this description it may be easier to explain transmission, but reception would be the same, just in the opposite direction.
In transmission mode the RF signal is applied to the feed patch 860 via connector 865 (e.g., a coaxial cable connector). As shown in
In one example the back plane insulator 850 is made of a Rogers® (FR-4 printed circuit board) and the feed patch 860 may be a conductive line formed on the Rogers. Rather than using Rogers, a PTFE (Polytetrafluoroethylene or Teflon®) or other low loss material may be used.
Thus, generally the embodiment of
By the embodiments disclosed above, an array antenna is provided, comprising: a variable dielectric constant (VDC) plate; a plurality of radiating patches provided in an array over the VDC plate; a plurality of variable delay lines provided over the VDC plate and below the radiating patches; a plurality of fixed delay lines provided over the VDC plate and below the radiating patches, each fixed delay line connected to one of the variable delay lines; a corporate feed having a plurality of ports; a ground plane; and a plurality of switches configured to selectively connect each of the ports to a selected variable delay line and to selectively connect each of the radiating patches to a selected fixed delay line. The antenna may have m fixed delay line, wherein n of the fixed delay lines introduce zero delay, and wherein n<m. The antenna may have m variable delay lines and n fixed delay lines, wherein n<m. Each of the switches may have one port and at least two throws. In the antenna, the variable delay lines may be provided on one layer and the fixed delay lines may be provided on a second layer above the first layer. Alternatively, the variable delay lines and the fixed delay lines may be provided on the same layer.
It should be understood that processes and techniques described herein are not inherently related to any particular apparatus and may be implemented by any suitable combination of components. Further, various types of general purpose devices may be used in accordance with the teachings described herein. The present invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations will be suitable for practicing the present invention.
Moreover, other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
Claims
1. An antenna, comprising:
- a plurality of radiators arranged in an array;
- a plurality of transmission lines, each coupled to one of the radiators;
- a plurality of variable phase shifters divided into a plurality of subgroups, each of the subgroups interposed between one of the transmission lines and one of the radiators;
- a controller outputting a signal indicative of amount of phase shift to be activated for each of the radiators;
- a switch interposed between the transmission lines and the plurality of variable phase shifters, the switch receiving the signal from the controller and connecting selected variable phase shifters to selected transmission lines according to the signal.
2. The antenna of claim 1, wherein each of the variable phase shifters introduces a phase shift of less than 360°.
3. The antenna of claim 1, wherein each of the variable phase shifters introduces a phase shift up to 360°/x, wherein x is a natural number of 2 or larger.
4. The antenna of claim 1, wherein each of the plurality of subgroups of variable phase shifters includes n variable phase shifters, and wherein each variable phase shifter within the group introduces a phase shift of up to 360°/n.
5. The antenna of claim 4, further comprising a plurality of fixed phase shifters, and wherein at least one of the variable phase shifters within each group is connected to one of the fixed phase shifters.
6. The antenna of claim 1, wherein each of the plurality of subgroups of variable phase shifters includes n variable phase shifters, and wherein each variable phase shifter within the group introduces a phase shift of up to (360°/n)+m, wherein m<(360°/n).
7. The antenna of claim 6, further comprising a plurality of fixed phase shifters, and wherein at least one of the variable phase shifters within each group is connected to one of the fixed phase shifters.
8. The antenna of claim 1, wherein the controller further output a potential signal indicative of the amount of electrical potential corresponding to the amount of phase shift to be activated for each of the radiators.
9. A multi-layer antenna array, comprising:
- a radiation layer comprising a plurality of radiating patches arranged in an array;
- a phase shift layer comprising a plurality of variable phase shifters arranged in sub-groups, each subgroup having at least two variable phase shifters;
- a ground plane layer comprising a conductive plate maintaining a common potential;
- an RF signal distribution layer comprising a plurality of RF conductors;
- a switch having multiple throws connected to the plurality of variable phase shifters and a pole connected to the plurality of RF conductors.
10. The antenna of claim 9, wherein the phase shift layer comprises a variable phase shift layer incorporating the plurality of variable phase shifters, and a fixed phase bias layer comprising a plurality of fixed phase shifters, each connected to one of the variable phase shifters.
11. The antenna of claim 10, wherein the switch comprises a plurality of multi-throw switches arranged within the variable phase shift layer, each having multiple throws connected to the variable phase shifters within one of the subgroups.
12. The antenna of claim 9, further comprising a variable dielectric constant (VDC) layer in contact with the phase shift layer.
13. The antenna of claim 10, further comprising a variable dielectric constant (VDC) layer in contact with the variable phase shift layer.
14. The antenna of claim 11, wherein the switch further comprises a plurality of multi-throw switches arranged within the fixed phase bias layer, each having multiple throws connected to a group of the fixed phase shifters and a pole coupled to one of the plurality of radiating patches.
15. The antenna of claim 10, wherein the plurality of fixed phase shifters comprises a plurality of signal lines of different lengths.
16. The antenna of claim 10, wherein the plurality of fixed phase shifters are arranged in groups, wherein in each group one fixed phase shifter introduces a phase shift of zero degrees and a second f phase shifter introduces a phase shift of 180°.
17. The antenna of claim 10, further comprising a plurality of vias, each via having one end connected to one of the variable phase shifters and another end connected to one of the fixed phase shifters.
18. An array antenna, comprising:
- a variable dielectric constant (VDC) plate;
- a plurality of radiating patches provided in an array over the VDC plate;
- a plurality of variable delay lines provided over the VDC plate and below the radiating patches;
- a plurality of fixed delay lines provided over the VDC plate and below the radiating patches, each fixed delay line connected to one of the variable delay lines;
- a corporate feed having a plurality of ports; a ground plane; and
- a plurality of switches configured to selectively connect each of the ports to a selected variable delay line and to selectively connect each of the radiating patches to a selected fixed delay line.
19. The antenna of claim 18, wherein the plurality of fixed delay lines comprises m fixed delay line, and wherein n of the fixed delay lines introduce zero delay, and wherein n<m.
20. The antenna of claim 18, wherein the plurality of variable delay lines comprises m variable delay lines, and the plurality of fixed delay line comprises n fixed delay lines, and wherein n<m.
Type: Application
Filed: Aug 15, 2023
Publication Date: Feb 22, 2024
Inventors: Rami Khair (Acre), Dedi David Haziza (Kiryat Motzkin)
Application Number: 18/234,343